1. Technical Field
The present invention relates to a liquid container which supplies liquid to a liquid consuming apparatus, such as a liquid ejecting head, from which a small amount of liquid droplets are discharged.
2. Related Art
A liquid ejecting head of a textile printing apparatus, a microdispenser, or an ink jet type recording apparatus for commercial use which is used for extremely high-quality printing, is supplied with liquid, which is to be discharged therefrom, from a liquid container. In this case, if the liquid ejecting head operates in a state where liquid is not supplied thereto, so-called idling occurs to thereby damage the ejecting head. Accordingly, it is necessary to monitor the remaining liquid amount of a container in order to prevent the damage.
Therefore, in the case of the recording apparatus, there have been proposed various kinds of ink cartridges, which serve as liquid containers which contain ink therein, in which a remaining liquid amount detecting unit that detects the remaining liquid amount is provided.
Ink cartridges mounted in the recording apparatus can be broadly classified into an atmosphere open type ink cartridge and a sealed type ink cartridge.
In the atmosphere open type ink cartridge, an atmosphere open hole communicates with an ink containing portion partitioned within the cartridge. In this case, since outside air is introduced into the ink containing portion as ink contained in the ink containing portion is consumed, atmospheric pressure can be used for supply of the ink from the ink cartridge toward the recording apparatus. Accordingly, since the configuration of a container may be simplified, the atmosphere open type ink cartridge is suitable for an ink cartridge having a relatively small capacity.
On the other hand, in the sealed type ink cartridge, an ink containing portion is formed using a flexible bag having a sealed structure, for example, such that deterioration of ink caused by coming in contact with the air can be suppressed. In this case, since the quality of contained ink can be stably maintained for a long time, the sealed type ink cartridge is suitable for an ink cartridge having a large capacity. However, since it is necessary to provide a pressure means for pressing a flexible bag, which is an ink containing portion, from the outside, sizes of the cartridge and a recording apparatus are easily increased compared with the atmosphere open type ink cartridge.
For this reason, in such a case of providing a remaining liquid amount detecting unit in an ink cartridge, it is important to make attachment of the remaining liquid amount detecting unit to the a cartridge case (container body) easy in order to improve the productivity by simplifying a cartridge assembly process.
Previously, an ink cartridge in which an attaching hole passing through an ink containing portion is formed in a container body having the ink containing portion and a remaining liquid amount detecting unit is fitted in the attaching hole by screwing has been developed as the atmosphere open type ink cartridge.
In this case, the remaining liquid amount detecting unit is configured to include a cylindrical portion which is attached to the attaching hole by screwing, a locking piece which is provided to protrude from the outer periphery of the cylindrical portion outward in the radial direction and which is fixed to the container body by being engaged with a locking portion provided in the container body when the cylindrical portion is operated by screwing, and a piezoelectric device embedded in the cylindrical portion, and the piezoelectric device detects the amount of remaining ink within the ink containing portion on the basis of remaining vibration with respect to vibration that is oscillation within the ink containing portion (for example, Patent Document 1).
In this ink cartridge, the remaining liquid amount detecting unit may be attached to the container body only by screwing the remaining liquid amount detecting unit to the attaching hole formed in the container body. Accordingly, since a cartridge assembly process becomes simplified, the productivity may be improved.
Patent Document 1: JP-A-2001-328280
However, in the case of the sealed type ink cartridge, the screw-type remaining liquid amount detecting unit adopted in the above atmosphere open type ink cartridge cannot be applied.
In the case of the atmosphere open type ink cartridge, a vibration characteristic within an ink containing chamber noticeably changes with consumption of ink due to outside air which is introduced into the ink containing chamber according to the consumption of ink. Accordingly, with simple measurement of remaining vibration using a piezoelectric device, the amount of remaining ink can be quite correctly detected, and the piezoelectric device may also be miniaturized.
However, in the case of the sealed type ink cartridge, the outside air is not introduced into the ink containing chamber even if ink is consumed. Accordingly, with the simple measurement of remaining vibration adopted in the atmosphere open type ink cartridge, the amount of remaining ink cannot be detected with high precision.
For this reason, a remaining liquid amount detecting unit that measures pressure (flow rate) changing with the amount of remaining ink has been proposed. However, in this case, the remaining liquid amount detecting unit is configured to include a passage into which remaining ink flows, a sensor which detects fluctuation in the amount of ink flowing to the passage, and the like. As a result, the remaining liquid amount detecting unit becomes large sized.
For example, in an ink cartridge, a circuit board having a contact point electrically connected to a connection terminal of a recording apparatus is provided on an outer surface of a container body and an information readable and writable memory device is mounted on the circuit board such that the amount of remaining ink can be more precisely controlled or various kinds of information for preventing incorrect mounting can be read and written from the recording apparatus side.
In the ink cartridge provided with such circuit board, if a terminal of a sensor in a remaining liquid amount detecting unit is electrically connected to a contact point on the circuit board through a relay terminal provided on the remaining liquid amount detecting unit, the sensor can be controlled from the recording apparatus side and wiring lines to the sensor can be simplified.
However, as described above, since the remaining liquid amount detecting unit becomes large sized in the sealed type ink cartridge, a relay terminal on the remaining liquid amount detecting unit makes a large rotational movement when the remaining liquid amount detecting unit is attached to the container body by rotation. At that time, positional deviation between a contact point on the circuit board and an end of the relay terminal may occur due to, for example, an attachment error caused by a dimensional tolerance, and as a result, there is a possibility that a trouble, such as poor contact, will occur.
For this reason, in the case of the sealed type ink cartridge, attachment based on a simple rotation operation cannot be adopted in an attachment structure of the remaining liquid amount detecting unit, and it takes time and effort to attach the remaining liquid amount detecting unit. As a result, a problem that an improvement in productivity is difficult occurs.